Roughing: uncut material remaining at 50% stepover

For stepover <= 50%, I think the innermost loop of a nest of offset paths should always clear its interior without leaving an uncut bit as can happen with stepover > 50%. If not so, then I’m misfiring here.

This first slice in this series is fine:


In the next slice down, shown in the middle, the triangles are too large. Simulation (!!!) shows the next layer started while uncut material remains at this level.


The clip on the right shows the same slice as the middle plus three more slices going down. In simulation, these shrinking triangles don’t shrink enough until the 4th layer down. This clip shows that same spike in the middle of the triangle grown three slices tall.


As the triangles shrink, the tool has to cut into the uncut material from the side. I’m already cutting to the depth my setup can manage. If it managed to cut the next layer after first leaving uncut material, the 3rd layer will almost certainly cost a broken bit or missed steps.

Before Thanksgiving I got around this by reducing stepover until KM added another inner loop to clear inside the “too big” triangles. That worked but made jobs slower with more loops than needed in other areas.

I’ll send an export.

I totally get what’s going on here. It’s actually very similar to a problem in FDM printing with small gaps between walls. And I’ve solved it there. But it’s invasive and not clean. So I would like to defer that solution to 2.5 as well.

Unexpected. I get how that would be for stepover >50%, but for <=50% it seems like path offsetting should “just work”.

But working on 2.5 seems like a better use of keystrokes than soothing my angst here. So I’ll call this topic done.

I do have one theory here, actually, since you’re working on really small parts. Send me your workspace and I’ll verify.

The export via discord earlier includes the part shown.

Do you want more little parts?

nope. just the settings you were using for slicing the part then

found a fix i think. these small parts seem ideal for finding corner cases.

?. It was a few megabytes iirc.

not the size of the file, the smallness of scale creating really tiny offset polygons which are being cleaned up as “junk”.

Appreciate your time to look in any case.

I’ll send some more parts with more corners :smiley:

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I think I misunderstood.

I think you meant: The export did include a part, and you don’t want more little parts but did want a settings export for the original example in this topic.

But since then you’ve absorbed this example, moved on, and don’t need this specific config export.

Or let me know if I’m still confused.

I found that I had everything I needed. Problem solved.

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